WESTON, Mass.--(BUSINESS WIRE)--Today Biogen Idec (NASDAQ: BIIB) announced the positive, full first-year
results from its two-year pivotal Phase 3 ADVANCE study of PLEGRIDY™(peginterferon
beta-1a), the company’s investigational candidate for
relapsing-remitting multiple sclerosis (RRMS) dosed once every two weeks
or every four weeks. These data, presented today at the American Academy
of Neurology’s 65th Annual Meeting, indicate that PLEGRIDY significantly
reduced multiple sclerosis (MS) disease activity, including relapses,
disability progression and brain lesions, compared to placebo at one
year.

“These full first-year results provide a more complete picture of
PLEGRIDY and its positive effects on the reduction of relapse,
disability progression and lesion development,” said Peter Calabresi,
M.D., director, the Johns Hopkins Multiple Sclerosis Center. “These data
suggest that, if approved, PLEGRIDY may offer the benefit of a less
frequent dosing schedule, which would be a meaningful advance for people
living with MS.”

Study Results for Two-Week Dosing Arm at Year One:

Primary endpoint:

PLEGRIDY met the primary endpoint of reducing annualized relapse rate
(ARR) at one year by 36 percent compared to placebo (p=0.0007).

Secondary endpoints:

PLEGRIDY reduced the proportion of patients who relapsed by 39 percent
compared to placebo (p=0.0003).

PLEGRIDY reduced the number of new or newly enlarging T2-hyperintense
lesions on brain MRI scans by 67 percent compared to placebo
(p<0.0001).

PLEGRIDY significantly reduced the number of gadolinium-enhancing
(Gd+) lesions by 86 percent compared to placebo (p<0.0001).

The incidence of PLEGRIDY neutralizing antibodies was less than 1
percent.

PLEGRIDY dosed once every four weeks was also shown to be effective, and
met the primary and secondary endpoints in the ADVANCE trial. PLEGRIDY
dosed once every two weeks resulted in a numerically greater treatment
effect across these relapse and MRI endpoints discussed above.

“In the first year of the ADVANCE trial, PLEGRIDY demonstrated strong
efficacy. We saw a marked reduction in relapse rate and this was
supported by MRI results. If approved, PLEGRIDY will make an important
therapeutic option in the injectable treatment segment”, said Gilmore
O’Neill, Vice President, Global Neurology Late Stage Clinical
Development at Biogen Idec. “In addition to these encouraging
therapeutic results, PLEGRIDY may reduce the treatment burden for
patients by reducing the number of subcutaneous injections.”

PLEGRIDY showed favorable safety and tolerability profiles in ADVANCE.
The overall incidence of serious adverse events (SAEs) and adverse
events (AEs) was similar among the PLEGRIDY and placebo groups. The most
common SAE was infections, which was balanced across all treatment
groups (≤1 percent per group). The most commonly reported AEs with
PLEGRIDY treatment were redness at the injection site and influenza-like
illness.

PLEGRIDY is a new molecular entity in which interferon beta-1a is
pegylated to extend its half-life and prolong its exposure in the body,
enabling study of a less frequent dosing schedule. PLEGRIDY is a member
of the interferon class of treatments and, if approved, would be a new
addition to this class, which is often used as a first-line treatment
for MS.

After completing two years in the ADVANCE study, patients have the
option of enrolling in an open-label extension study called ATTAIN and
will be followed for up to four years.

The two-year Phase 3 ADVANCE clinical trial is a global, multi-center,
randomized, double-blind, parallel-group, placebo-controlled study
designed to evaluate the efficacy and safety of PLEGRIDY in 1,516
randomized patients with RRMS.

The study investigates two dose regimens of PLEGRIDY, 125 mcg
administered subcutaneously every two weeks or every four weeks compared
to placebo. The analysis for all primary and secondary efficacy
endpoints occurs at one year. After the first year, patients on placebo
are re-randomized to one of the PLEGRIDY arms for the duration of the
second year of the study.

About Biogen Idec

Through cutting-edge science and medicine, Biogen Idec discovers,
develops and delivers to patients worldwide innovative therapies for the
treatment of neurodegenerative diseases, hemophilia and autoimmune
disorders. Founded in 1978, Biogen Idec is the world’s oldest
independent biotechnology company. Patients worldwide benefit from its
leading multiple sclerosis therapies, and the company generates more
than $5 billion in annual revenues. For product labeling, press releases
and additional information about the company, please visit www.biogenidec.com.

Safe Harbor

This press release contains forward-looking statements, including
statements about the dosage and related therapeutic effects, development
and commercialization of PLEGRIDY™ (peginterferon beta-1a). These
statements may be identified by words such as "believe," "expect,"
"may," "plan," "potential," "will" and similar expressions, and are
based on our current beliefs and expectations. Drug development and
commercialization involve a high degree of risk. Factors which could
cause actual results to differ materially from our current expectations
include the risk that unexpected concerns may arise from additional data
or analysis, regulatory authorities may require additional information
or further studies, or may fail to approve or may delay approval of our
drug candidates, or we may encounter other unexpected hurdles. For more
detailed information on the risks and uncertainties associated with our
drug development and commercialization activities, please review the
Risk Factors section of our most recent annual or quarterly report filed
with the Securities and Exchange Commission. Any forward-looking
statements speak only as of the date of this press release and we assume
no obligation to update any forward-looking statements.